What Do You Know about the Adhan?

The Adhan is the sound heard five times a day around the world summoning Muslims to prayer where in unison they, facing the Ka`bah, stand between the hands of God, professing their love to Him and worshipping Him.

So, what do you know about that call; what does it calling Muslims to, and what does the word itself mean?

How was it introduced into Islam? Who was the first to suggest the call to prayer? How did it develop throughout history?

Who is the first muezzin (caller to prayer) in Islamic history? Where was the first Adhan given?